Swimwear is a segment of the garment industry which is known to have special needs and requirements. Swimwear is typically constructed from knit fabrics as knit fabrics can more easily conform to the body by compressing or elongating the individual knit stitches that form the knit fabric. However, the ability of the stitches to conform or elongate also leads to deformations such as bagging, particularly in areas where the garment is subjected to more stretching, unless the fabric has the ability to return the knit stitches to their original dimensions. These deformation tend to become exaggerated in an aqueous environment such as encountered in swimming. Bagging is not only unsightly, but also increases the drag as the swimmer moves through the water. Accordingly, it is desired to produce a knit fabric having elastomeric properties such that swimwear or other garments made from the fabric will be more dimensionally stable.
Fabrics containing elastic fiber are well known. It is now common to co-knit a relatively small amount of an elastic fiber such as spandex with a companion hard yarn. Due to the nature of most elastic fibers, a heat setting step is usually required to maintain dimensional stability. Without such heat-setting, the elastic fiber will retract to compress the fabric stitches, thereby reducing the overall dimensions. Heat setting is known to have several disadvantages including cost, and undesired reactions of the elastic and/or companion yarns to the heat. To combat the reaction to the heat, elastic fibers that can be heat-set at somewhat lower temperatures have been identified (see, for example U.S. Pat. Nos. 5,948,875 or 6,472,494). Another approach was reported in US2006/0021387 A1, which discloses circular knit elastic fabrics which include a bare elastomeric material such as spandex plated with spun or continuous filament hard yarns. The fabric is subjected to an aqueous setting procedure referred to as “hydro-setting”, under particular temperature and pressure conditions. It is desired to have a dimensionally stable fabric which does not require traditional high temperature heat-setting or hydro setting.
US2005/0164577 A1 discloses circular knit stretch fabrics made from crosslinked olefinic elastic fiber. These fabrics show improved growth characteristics but still lack the desired dimensional stability. Accordingly it is desired to have a fabric with even greater dimensional stability, particularly under conditions such as those encountered by competitive swimmers. It is also desirable to have improved dimensional stability to allow for greater flexibility in final garment treatments such as printing.
It has been discovered that improved fabrics comprising elastic fiber together with hard companion yarns can be obtained by using knitting conditions such as feed rates and fine gauge needles to produce a fine tight loop. Moreover, it has also been discovered that dimensional stability can be improved by selecting hard yarns that exhibit an inherent elastic response, either as a result of chemical nature of the fiber or which has been introduced during the fiber production process, such as a texturization process.
Accordingly, one aspect of the present invention is an elastic fabric characterized in that it has an Elongation greater than 90%, an instantaneous fabric growth at 15% strain of 7% or less, a Dimensional Stability for each of the length and the width of ±7%, wherein the fabric comprises from 6% to 50% by weight of a first fiber which is a crosslinked polyolefin fiber of from 11 to 99 dtex, and from 50% to 94% by weight of a second fiber which is a fiber of from 22 to 176 dtex selected from the group consisting of polyester, nylon, and polypropylene.
Another aspect of the present invention is a garment, particularly swimwear, made from the preferred fabric of the invention.
Still another aspect of the present invention is a method for making a dimensionally stable elastic fabric comprising combining a first fiber which is a crosslinked polyolefin fiber of from 11 to 99 dtex, and a second fiber selected from the group consisting of polyester, nylon, and polypropylene which second fiber is a fiber of from 22 to 176 dtex under knitting conditions suitable to produce a fine tight loop (e.g. 1000 to 1600 mm/rack for the hard yarn with 200 to 1000 mm/rack for the elastic yarn).